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</script></head><body><div id="package-header"><ul class="links" id="page-menu"><li><a href="src/Control-Monad-Trans-RWS-Strict.html">Source</a></li><li><a href="index.html">Contents</a></li><li><a href="doc-index.html">Index</a></li></ul><p class="caption">transformers-0.2.2.0: Concrete functor and monad transformers</p></div><div id="content"><div id="module-header"><table class="info"><tr><th>Portability</th><td>portable</td></tr><tr><th>Stability</th><td>experimental</td></tr><tr><th>Maintainer</th><td>ross@soi.city.ac.uk</td></tr></table><p class="caption">Control.Monad.Trans.RWS.Strict</p></div><div id="table-of-contents"><p class="caption">Contents</p><ul><li><a href="#g:1">The RWS monad
</a></li><li><a href="#g:2">The RWST monad transformer
</a></li><li><a href="#g:3">Reader operations
</a></li><li><a href="#g:4">Writer operations
</a></li><li><a href="#g:5">State operations
</a></li><li><a href="#g:6">Lifting other operations
</a></li></ul></div><div id="description"><p class="caption">Description</p><div class="doc"><p>A monad transformer that combines <code>ReaderT</code>, <code>WriterT</code> and <code>StateT</code>.
This version is strict; for a lazy version, see
<a href="Control-Monad-Trans-RWS-Lazy.html">Control.Monad.Trans.RWS.Lazy</a>, which has the same interface.
</p></div></div><div id="synopsis"><p id="control.syn" class="caption expander" onclick="toggleSection('syn')">Synopsis</p><ul id="section.syn" class="hide" onclick="toggleSection('syn')"><li class="src short"><span class="keyword">type</span> <a href="#t:RWS">RWS</a> r w s = <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s <a href="Data-Functor-Identity.html#t:Identity">Identity</a></li><li class="src short"><a href="#v:rws">rws</a> :: (r -> s -> (a, s, w)) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWS">RWS</a> r w s a</li><li class="src short"><a href="#v:runRWS">runRWS</a> :: <a href="Control-Monad-Trans-RWS-Strict.html#t:RWS">RWS</a> r w s a -> r -> s -> (a, s, w)</li><li class="src short"><a href="#v:evalRWS">evalRWS</a> :: <a href="Control-Monad-Trans-RWS-Strict.html#t:RWS">RWS</a> r w s a -> r -> s -> (a, w)</li><li class="src short"><a href="#v:execRWS">execRWS</a> :: <a href="Control-Monad-Trans-RWS-Strict.html#t:RWS">RWS</a> r w s a -> r -> s -> (s, w)</li><li class="src short"><a href="#v:mapRWS">mapRWS</a> :: ((a, s, w) -> (b, s, w')) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWS">RWS</a> r w s a -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWS">RWS</a> r w' s b</li><li class="src short"><a href="#v:withRWS">withRWS</a> :: (r' -> s -> (r, s)) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWS">RWS</a> r w s a -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWS">RWS</a> r' w s a</li><li class="src short"><span class="keyword">newtype</span> <a href="#t:RWST">RWST</a> r w s m a = <a href="#v:RWST">RWST</a> {<ul class="subs"><li><a href="#v:runRWST">runRWST</a> :: r -> s -> m (a, s, w)</li></ul>}</li><li class="src short"><a href="#v:evalRWST">evalRWST</a> :: <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m => <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a -> r -> s -> m (a, w)</li><li class="src short"><a href="#v:execRWST">execRWST</a> :: <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m => <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a -> r -> s -> m (s, w)</li><li class="src short"><a href="#v:mapRWST">mapRWST</a> :: (m (a, s, w) -> n (b, s, w')) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w' s n b</li><li class="src short"><a href="#v:withRWST">withRWST</a> :: (r' -> s -> (r, s)) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r' w s m a</li><li class="src short"><a href="#v:ask">ask</a> :: (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m r</li><li class="src short"><a href="#v:local">local</a> :: (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => (r -> r) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a</li><li class="src short"><a href="#v:asks">asks</a> :: (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => (r -> a) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a</li><li class="src short"><a href="#v:tell">tell</a> :: (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => w -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m <a href="/usr/share/doc/ghc/html/libraries/ghc-prim-0.2.0.0/GHC-Unit.html#t:-40--41-">()</a></li><li class="src short"><a href="#v:listen">listen</a> :: (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m (a, w)</li><li class="src short"><a href="#v:listens">listens</a> :: (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => (w -> b) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m (a, b)</li><li class="src short"><a href="#v:pass">pass</a> :: (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m (a, w -> w) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a</li><li class="src short"><a href="#v:censor">censor</a> :: (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => (w -> w) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a</li><li class="src short"><a href="#v:get">get</a> :: (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m s</li><li class="src short"><a href="#v:put">put</a> :: (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => s -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m <a href="/usr/share/doc/ghc/html/libraries/ghc-prim-0.2.0.0/GHC-Unit.html#t:-40--41-">()</a></li><li class="src short"><a href="#v:modify">modify</a> :: (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => (s -> s) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m <a href="/usr/share/doc/ghc/html/libraries/ghc-prim-0.2.0.0/GHC-Unit.html#t:-40--41-">()</a></li><li class="src short"><a href="#v:gets">gets</a> :: (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => (s -> a) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a</li><li class="src short"><a href="#v:liftCallCC">liftCallCC</a> :: <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w => ((((a, s, w) -> m (b, s, w)) -> m (a, s, w)) -> m (a, s, w)) -> ((a -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m b) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a</li><li class="src short"><a href="#v:liftCallCC-39-">liftCallCC'</a> :: <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w => ((((a, s, w) -> m (b, s, w)) -> m (a, s, w)) -> m (a, s, w)) -> ((a -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m b) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a</li><li class="src short"><a href="#v:liftCatch">liftCatch</a> :: (m (a, s, w) -> (e -> m (a, s, w)) -> m (a, s, w)) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> l w s m a -> (e -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> l w s m a) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> l w s m a</li></ul></div><div id="interface"><h1 id="g:1">The RWS monad
</h1><div class="top"><p class="src"><span class="keyword">type</span> <a name="t:RWS" class="def">RWS</a> r w s = <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s <a href="Data-Functor-Identity.html#t:Identity">Identity</a><a href="src/Control-Monad-Trans-RWS-Strict.html#RWS" class="link">Source</a></p><div class="doc"><p>A monad containing an environment of type <code>r</code>, output of type <code>w</code>
and an updatable state of type <code>s</code>.
</p></div></div><div class="top"><p class="src"><a name="v:rws" class="def">rws</a> :: (r -> s -> (a, s, w)) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWS">RWS</a> r w s a<a href="src/Control-Monad-Trans-RWS-Strict.html#rws" class="link">Source</a></p><div class="doc"><p>Construct an RWS computation from a function.
(The inverse of <code><a href="Control-Monad-Trans-RWS-Strict.html#v:runRWS">runRWS</a></code>.)
</p></div></div><div class="top"><p class="src"><a name="v:runRWS" class="def">runRWS</a> :: <a href="Control-Monad-Trans-RWS-Strict.html#t:RWS">RWS</a> r w s a -> r -> s -> (a, s, w)<a href="src/Control-Monad-Trans-RWS-Strict.html#runRWS" class="link">Source</a></p><div class="doc"><p>Unwrap an RWS computation as a function.
(The inverse of <code><a href="Control-Monad-Trans-RWS-Strict.html#v:rws">rws</a></code>.)
</p></div></div><div class="top"><p class="src"><a name="v:evalRWS" class="def">evalRWS</a> :: <a href="Control-Monad-Trans-RWS-Strict.html#t:RWS">RWS</a> r w s a -> r -> s -> (a, w)<a href="src/Control-Monad-Trans-RWS-Strict.html#evalRWS" class="link">Source</a></p></div><div class="top"><p class="src"><a name="v:execRWS" class="def">execRWS</a> :: <a href="Control-Monad-Trans-RWS-Strict.html#t:RWS">RWS</a> r w s a -> r -> s -> (s, w)<a href="src/Control-Monad-Trans-RWS-Strict.html#execRWS" class="link">Source</a></p></div><div class="top"><p class="src"><a name="v:mapRWS" class="def">mapRWS</a> :: ((a, s, w) -> (b, s, w')) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWS">RWS</a> r w s a -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWS">RWS</a> r w' s b<a href="src/Control-Monad-Trans-RWS-Strict.html#mapRWS" class="link">Source</a></p></div><div class="top"><p class="src"><a name="v:withRWS" class="def">withRWS</a> :: (r' -> s -> (r, s)) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWS">RWS</a> r w s a -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWS">RWS</a> r' w s a<a href="src/Control-Monad-Trans-RWS-Strict.html#withRWS" class="link">Source</a></p></div><h1 id="g:2">The RWST monad transformer
</h1><div class="top"><p class="src"><span class="keyword">newtype</span> <a name="t:RWST" class="def">RWST</a> r w s m a <a href="src/Control-Monad-Trans-RWS-Strict.html#RWST" class="link">Source</a></p><div class="doc"><p>A monad transformer adding reading an environment of type <code>r</code>,
collecting an output of type <code>w</code> and updating a state of type <code>s</code>
to an inner monad <code>m</code>.
</p></div><div class="subs constructors"><p class="caption">Constructors</p><table><tr><td class="src"><a name="v:RWST" class="def">RWST</a></td><td class="doc empty"> </td></tr><tr><td colspan="2"><div class="subs fields"><p class="caption">Fields</p><dl><dt class="src"><a name="v:runRWST" class="def">runRWST</a> :: r -> s -> m (a, s, w)</dt><dd class="doc empty"> </dd></dl><div class="clear"></div></div></td></tr></table></div><div class="subs instances"><p id="control.i:RWST" class="caption collapser" onclick="toggleSection('i:RWST')">Instances</p><div id="section.i:RWST" class="show"><table><tr><td class="src"><a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w => <a href="Control-Monad-Trans-Class.html#t:MonadTrans">MonadTrans</a> (<a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s)</td><td class="doc empty"> </td></tr><tr><td class="src">(<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> (<a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m)</td><td class="doc empty"> </td></tr><tr><td class="src"><a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Functor">Functor</a> m => <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Functor">Functor</a> (<a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m)</td><td class="doc empty"> </td></tr><tr><td class="src">(<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad-Fix.html#t:MonadFix">MonadFix</a> m) => <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad-Fix.html#t:MonadFix">MonadFix</a> (<a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m)</td><td class="doc empty"> </td></tr><tr><td class="src">(<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:MonadPlus">MonadPlus</a> m) => <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:MonadPlus">MonadPlus</a> (<a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m)</td><td class="doc empty"> </td></tr><tr><td class="src">(<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Functor">Functor</a> m, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Applicative.html#t:Applicative">Applicative</a> (<a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m)</td><td class="doc empty"> </td></tr><tr><td class="src">(<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Functor">Functor</a> m, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:MonadPlus">MonadPlus</a> m) => <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Applicative.html#t:Alternative">Alternative</a> (<a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m)</td><td class="doc empty"> </td></tr><tr><td class="src">(<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="Control-Monad-IO-Class.html#t:MonadIO">MonadIO</a> m) => <a href="Control-Monad-IO-Class.html#t:MonadIO">MonadIO</a> (<a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m)</td><td class="doc empty"> </td></tr></table></div></div></div><div class="top"><p class="src"><a name="v:evalRWST" class="def">evalRWST</a> :: <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m => <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a -> r -> s -> m (a, w)<a href="src/Control-Monad-Trans-RWS-Strict.html#evalRWST" class="link">Source</a></p></div><div class="top"><p class="src"><a name="v:execRWST" class="def">execRWST</a> :: <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m => <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a -> r -> s -> m (s, w)<a href="src/Control-Monad-Trans-RWS-Strict.html#execRWST" class="link">Source</a></p></div><div class="top"><p class="src"><a name="v:mapRWST" class="def">mapRWST</a> :: (m (a, s, w) -> n (b, s, w')) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w' s n b<a href="src/Control-Monad-Trans-RWS-Strict.html#mapRWST" class="link">Source</a></p></div><div class="top"><p class="src"><a name="v:withRWST" class="def">withRWST</a> :: (r' -> s -> (r, s)) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r' w s m a<a href="src/Control-Monad-Trans-RWS-Strict.html#withRWST" class="link">Source</a></p></div><h1 id="g:3">Reader operations
</h1><div class="top"><p class="src"><a name="v:ask" class="def">ask</a> :: (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m r<a href="src/Control-Monad-Trans-RWS-Strict.html#ask" class="link">Source</a></p><div class="doc"><p>Fetch the value of the environment.
</p></div></div><div class="top"><p class="src"><a name="v:local" class="def">local</a> :: (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => (r -> r) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a<a href="src/Control-Monad-Trans-RWS-Strict.html#local" class="link">Source</a></p><div class="doc"><p>Execute a computation in a modified environment
</p></div></div><div class="top"><p class="src"><a name="v:asks" class="def">asks</a> :: (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => (r -> a) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a<a href="src/Control-Monad-Trans-RWS-Strict.html#asks" class="link">Source</a></p><div class="doc"><p>Retrieve a function of the current environment.
</p></div></div><h1 id="g:4">Writer operations
</h1><div class="top"><p class="src"><a name="v:tell" class="def">tell</a> :: (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => w -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m <a href="/usr/share/doc/ghc/html/libraries/ghc-prim-0.2.0.0/GHC-Unit.html#t:-40--41-">()</a><a href="src/Control-Monad-Trans-RWS-Strict.html#tell" class="link">Source</a></p><div class="doc"><p><code><code><a href="Control-Monad-Trans-RWS-Strict.html#v:tell">tell</a></code> w</code> is an action that produces the output <code>w</code>.
</p></div></div><div class="top"><p class="src"><a name="v:listen" class="def">listen</a> :: (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m (a, w)<a href="src/Control-Monad-Trans-RWS-Strict.html#listen" class="link">Source</a></p><div class="doc"><p><code><code><a href="Control-Monad-Trans-RWS-Strict.html#v:listen">listen</a></code> m</code> is an action that executes the action <code>m</code> and adds its
output to the value of the computation.
</p></div></div><div class="top"><p class="src"><a name="v:listens" class="def">listens</a> :: (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => (w -> b) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m (a, b)<a href="src/Control-Monad-Trans-RWS-Strict.html#listens" class="link">Source</a></p><div class="doc"><p><code><code><a href="Control-Monad-Trans-RWS-Strict.html#v:listens">listens</a></code> f m</code> is an action that executes the action <code>m</code> and adds
the result of applying <code>f</code> to the output to the value of the computation.
</p><ul><li><pre><code><a href="Control-Monad-Trans-RWS-Strict.html#v:listens">listens</a></code> f m = <code><a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#v:liftM">liftM</a></code> (id *** f) (<code><a href="Control-Monad-Trans-RWS-Strict.html#v:listen">listen</a></code> m)</pre></li></ul></div></div><div class="top"><p class="src"><a name="v:pass" class="def">pass</a> :: (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m (a, w -> w) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a<a href="src/Control-Monad-Trans-RWS-Strict.html#pass" class="link">Source</a></p><div class="doc"><p><code><code><a href="Control-Monad-Trans-RWS-Strict.html#v:pass">pass</a></code> m</code> is an action that executes the action <code>m</code>, which returns
a value and a function, and returns the value, applying the function
to the output.
</p></div></div><div class="top"><p class="src"><a name="v:censor" class="def">censor</a> :: (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => (w -> w) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a<a href="src/Control-Monad-Trans-RWS-Strict.html#censor" class="link">Source</a></p><div class="doc"><p><code><code><a href="Control-Monad-Trans-RWS-Strict.html#v:censor">censor</a></code> f m</code> is an action that executes the action <code>m</code> and
applies the function <code>f</code> to its output, leaving the return value
unchanged.
</p><ul><li><pre><code><a href="Control-Monad-Trans-RWS-Strict.html#v:censor">censor</a></code> f m = <code><a href="Control-Monad-Trans-RWS-Strict.html#v:pass">pass</a></code> (<code><a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#v:liftM">liftM</a></code> (\x -> (x,f)) m)</pre></li></ul></div></div><h1 id="g:5">State operations
</h1><div class="top"><p class="src"><a name="v:get" class="def">get</a> :: (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m s<a href="src/Control-Monad-Trans-RWS-Strict.html#get" class="link">Source</a></p><div class="doc"><p>Fetch the current value of the state within the monad.
</p></div></div><div class="top"><p class="src"><a name="v:put" class="def">put</a> :: (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => s -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m <a href="/usr/share/doc/ghc/html/libraries/ghc-prim-0.2.0.0/GHC-Unit.html#t:-40--41-">()</a><a href="src/Control-Monad-Trans-RWS-Strict.html#put" class="link">Source</a></p><div class="doc"><p><code><code><a href="Control-Monad-Trans-RWS-Strict.html#v:put">put</a></code> s</code> sets the state within the monad to <code>s</code>.
</p></div></div><div class="top"><p class="src"><a name="v:modify" class="def">modify</a> :: (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => (s -> s) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m <a href="/usr/share/doc/ghc/html/libraries/ghc-prim-0.2.0.0/GHC-Unit.html#t:-40--41-">()</a><a href="src/Control-Monad-Trans-RWS-Strict.html#modify" class="link">Source</a></p><div class="doc"><p><code><code><a href="Control-Monad-Trans-RWS-Strict.html#v:modify">modify</a></code> f</code> is an action that updates the state to the result of
applying <code>f</code> to the current state.
</p></div></div><div class="top"><p class="src"><a name="v:gets" class="def">gets</a> :: (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#t:Monad">Monad</a> m) => (s -> a) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a<a href="src/Control-Monad-Trans-RWS-Strict.html#gets" class="link">Source</a></p><div class="doc"><p>Get a specific component of the state, using a projection function
supplied.
</p><ul><li><pre><code><a href="Control-Monad-Trans-RWS-Strict.html#v:gets">gets</a></code> f = <code><a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Control-Monad.html#v:liftM">liftM</a></code> f <code><a href="Control-Monad-Trans-RWS-Strict.html#v:get">get</a></code></pre></li></ul></div></div><h1 id="g:6">Lifting other operations
</h1><div class="top"><p class="src"><a name="v:liftCallCC" class="def">liftCallCC</a> :: <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w => ((((a, s, w) -> m (b, s, w)) -> m (a, s, w)) -> m (a, s, w)) -> ((a -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m b) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a<a href="src/Control-Monad-Trans-RWS-Strict.html#liftCallCC" class="link">Source</a></p><div class="doc"><p>Uniform lifting of a <code>callCC</code> operation to the new monad.
This version rolls back to the original state on entering the
continuation.
</p></div></div><div class="top"><p class="src"><a name="v:liftCallCC-39-" class="def">liftCallCC'</a> :: <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Monoid.html#t:Monoid">Monoid</a> w => ((((a, s, w) -> m (b, s, w)) -> m (a, s, w)) -> m (a, s, w)) -> ((a -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m b) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> r w s m a<a href="src/Control-Monad-Trans-RWS-Strict.html#liftCallCC%27" class="link">Source</a></p><div class="doc"><p>In-situ lifting of a <code>callCC</code> operation to the new monad.
This version uses the current state on entering the continuation.
</p></div></div><div class="top"><p class="src"><a name="v:liftCatch" class="def">liftCatch</a> :: (m (a, s, w) -> (e -> m (a, s, w)) -> m (a, s, w)) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> l w s m a -> (e -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> l w s m a) -> <a href="Control-Monad-Trans-RWS-Strict.html#t:RWST">RWST</a> l w s m a<a href="src/Control-Monad-Trans-RWS-Strict.html#liftCatch" class="link">Source</a></p><div class="doc"><p>Lift a <code>catchError</code> operation to the new monad.
</p></div></div></div></div><div id="footer"><p>Produced by <a href="http://www.haskell.org/haddock/">Haddock</a> version 2.9.2</p></div></body></html>
